Question

The cost of leveling a triangular piece of land whose sides are 72 m. 30 m and 78 in respectively at the rate of 20 paisa per square metre is:

A) ₹ 220 B) ₹ 200 C) ₹ 216 D) ₹ 210

Answer 1

Given:-

$\implies$Rate of cost = 20 paise/m²

$\implies$ = 0.2/ m²

$\implies$Side of triangle = 72m , 30m , 78m

To Find:-

$\implies$ cost of leveling = ?

Solution:-

Let the side of triangle be a = 72 m

b = 30 m

c = 78 m

so, S = $\frac{a+b+c}{2}$ = $\frac{ 72+30+78}{2}$ = $\frac{180}{2}$ = 90

Now, using herons formula

Area $\implies$ $\sqrt{s(s-a)(a-b)s-c)}$

$\implies$ $\sqrt{90(90-72)(90-30)(90-78)}$

$\implies$ $\sqrt{90×18×60×12}$

$\implies$ $\sqrt{1166400}$

$\implies$ $1080$ m²

Cost of leveling = Rate ×area

$\implies$ 0.2× 1080

$\implies$ ₹ 216 ...ans.....